This PDF file contains the front matter associated with SPIE Proceedings Volume 11935, including the Title Page, Copyright information, Table of Contents, and Conference Committee listings.

A potential new method of neural stimulation in cochlear implants (CIs) is light. It could improve the performance of cochlear implant users in speech, speech in noise, and music perception by increasing the spectral selectivity and number of independent channels. Inserting bundles of optical waveguides into the scala tympani of the cochlea is one possible method to deliver light to the spiral ganglion neurons. In this study, we tested waveguides made of OrmoComp®, a hybrid polymer. Waveguides were fabricated via injection molding and coated using dip-coating or thermal reflow. The resulting core diameters of the waveguides were 300 μm with outer diameters of 306 and 940 μm, respectively. For the 306 μm total diameter waveguides, the coupling losses were 10.4 ± 2.7, 4.3 ± 2.7, 6.0 ± 2.3, 6.3 ± 1.4, 6.6 ± 2.5, and 23. ± 3.6 dB, at l=405, l=534, l=680, l=1375, l=1460, and l=1550 nm, respectively. The propagation losses at the same wavelengths were 0.8 ± 1.4, 1.4 ± 1.4, 0 ± 1.2, 0 ± 0.7, 2.0 ± 1.5, and 3.1 ± 1.8 dB/cm, respectively. Bending losses for 360 degrees at l=1375 nm were 5.0, 2.4, and 0.46 for a bending radius of 2.5, 3, and 4 mm, respectively. Insertion forces for the 306 μm diameter waveguides into an acrylic human-size scala tympani model were about 100 mN. For the 940 μm total diameter waveguides, the coupling losses were 0.96 ± 1.4, 1.4 ± 1.0, 0.1 ± 0.56, 1.5 ± 0.45, 0.7 ± 1.3, and 0 ± 1.56 dB, at l=405, l=534, l=680, l=1375, l=1460, and l=1550 nm, respectively. The propagation losses at the same wavelengths were 2.2 ± 0.46, 0.6 ± 0.32, 0.87 ± 0.18, 1.46 ± 0.14, 3.7 ± 0.61, and 2.42 ± 0.54 dB/cm, respectively. Waveguides were also fabricated by injecting OrmoComp® into polyimide tubing, 132-μm outer and 100-μm inner diameter, followed by curing OrmoComp® with ultraviolet (UV) light at l=365 nm for 5 minutes. The coupling losses for the OrmoComp® filled 100- μm core diameter waveguides were less than 1 dB, and the propagation losses were 3.7 dB/cm. The coupling was not optimized in our measurements, and losses can be reduced. Propagation losses are more challenging to address because they depend on the waveguide's material properties and cladding. The bending stiffness of a 1000 μm segment of the 100- μm-diameter waveguides was 18.9 ± 2.2 N/m. Mechanical properties compare well with corresponding measures obtained from conventional cochlear implant electrodes.

Surgical excision of an adenomatous or hypercellular parathyroid gland is typically the treatment of choice for primary hyperparathyroidism. Intraoperative identification can be challenging due to potential variable location and indistinct features of these glands. In 115 ex-vivo specimens we evaluated the efficacy of DOCI in identifying hypercellular parathyroid glands. Significant imaging differences were seen between hypercellular vs normal parathyroid glands vs other adjacent healthy tissues across 8 spectral channels (p<0.05). Our classification result (100% sensitivity, 98.8% specificity) using a logistic regression classifier further corroborated that DOCI has the capacity to accurately identify and differentiate parathyroid glands from surrounding tissues. DOCI enables sensitive and specific mapping of parathyroid location, leading to improved accuracy of the surgical procedure, reduced time to successful completion, fewer risks and improved patient outcomes.

Parathyroid glands (PGs), small endocrine glands in the neck, control calcium levels in the body and are crucial to maintaining homeostasis. Accidental removal of or direct damage to healthy parathyroid glands during thyroid surgery may occur due to its small size and similar appearance to surrounding anatomical structures, potentially leading to postoperative hypocalcemia. Thus precise and quick detection of normal parathyroid glands in real-time during surgery can improve the surgical outcome. In this study, we introduce a deep learning system (YOLOv5) based on dual RGB/NIR imaging for Computer-aided detection (CADe) of PG with high accuracy. This model can effectively detect parathyroid glands in real-time as it also includes the confidence level, which can help surgeons make decisions. We tested a computer-aided detection (CADe) using the co-registered RGB/NIR camera and ex-vivo thyroid tissue specimen. The average precisions of models were significantly higher when trained by the dual-RGB/NIR (0.99) data than NIR (0.94) and RGB (0.96) data alone at a high confidence threshold (0.7). The proposed CADe may increase the parathyroid detection rates clinically.

Mucociliary clearance facilitated by healthy cilia beating is crucial to normal upper airway function. Phase-contrast microscopy (PCM) is the current golden standard for measuring ciliary beat frequency (CBF) and has limitations. With PCM, one cannot appreciate how CBF varies across the complex landscape of the nasal vault and sinus tissues. With Spectrally encoded interferometric microscopy (SEIM), en face imaging of cilia can be achieved, providing insight into the changes in CBF across tissue surfaces. This study aims to validate the use of SEIM to quantify ciliary beat frequency across ex vivo upper airway tissue.

Due to the anatomic confines of the head and neck, resection of oropharyngeal squamous cell carcinoma (OPSCC) necessitates precise margins that balance oncologic outcomes with preservation of speech and swallowing. Dynamic Optical Contrast Imaging (DOCI) is a novel non-invasive imaging system that measures endogenous fluorescence decay rates. DOCI acquires images in real-time (<2 secs) with an operatively relevant wide field of view (6.5 cm²). After surgical excision, 10 OPSCC specimens were imaged using DOCI. In all 10 specimens, DOCI clearly differentiated healthy tissue from cancer (p<0.01). DOCI has the potential to improve patient oncologic and functional outcomes by allowing the surgeon to precisely determine margins intraoperatively.

Precision molecular imaging finds application in the delineation of tumor margins during surgical resection of head and neck cancers (HNCs). Despite the advantages of surgery, there remain challenges in successfully locating tumor margins, resecting the entire tumor volume and treatment of microscopic tumor tissue. The presence of residual tumors, post-surgery, may require additional interventions and often lead to tumor recurrence. While Epidermal growth factor receptor (EGFR) remains a receptor of choice for targeting in HNCs, the heterogeneity in the expression of EGFR often leads to variations in response to targeted therapeutics. To improve visualization and tumor margin delineation during head and neck tumor surgeries, this study demonstrates the development of a molecular targeted theranostic probe combining the complementary features of fluorescence and photoacoustic imaging. The probe: DFAC (Dual Function Antibody Conjugate) comprises of a fluorophore/photosensitizer; Benzoporphyrin derivative (BPD) and a photoacoustic contrast agent; naphthalocyanine (NC) derivative conjugated to an EGFR antibody; Cetuximab. While BPD assists in fluorescence imaging, it can also be used for inducing cytotoxicity, through photodynamic activation in target tissues. The efficacy of DFAC in selective visualization and photodynamic therapy of tumor cells is evaluated on heterocellular 3D tumor spheroids and orthotopic mouse tongue tumors developed from human oral cancer cell lines (CAL27 and SCC4), expressing different levels of EGFR. In summary, this study demonstrates the potential of the theranostic probe (DFAC) to delineate tumor regions for guiding surgical resection and eradicate residual tumor tissue (post-surgery) by photodynamic therapy.

Scar formation in tissue is a healing process that inhibits normal tissue function through the deposition of predominantly disorganized type I collagen which is much more rigid than native collagen. Scarring in the vocal fold is especially debilitating as the vocal fold requires flexibility and freedom of movement to produce voicing. Furthermore the vocal fold has a very layered and organized structure with type I collagen in the basement membrane providing organ structural support, while type III collagen is in high concentration in the deep layer of the vocal fold. Using Dynamic Optical Contrast Imaging (DOCI) on unstained histological rabbit vocal fold slides (formalin fixed paraffin embedded tissue, FFPE), we were able to use subtle differences in fluorescence lifetime between native and scarred collagen types to image molecular evolution of scarring following injury. The degree of scarring and the DOCI fluorescence life time shift correlated with molecular and functional evaluations of scarring. Preliminary results demonstrates DOCI could be used as a prognostic tool useful to clinicians by depicting scar damage on vocal folds, (VF) not visible to the unaided eye or with white light endoscopic imaging.

Facial nerve (FN) palsies consist of paralysis of unknown origin potentially caused by metabolic disorders, trauma, and infectious diseases. Currently, FN injuries diagnosed as Bell's Palsy (BP) are characterized by total involvement of the affected hemiface, leading to multiple consequences including lack of eye lubrication. Our study employed low-level laser therapy (LLLT) for recovery of FN palsies by patient 1 with BP and patient 2 with trauma. Our LLLT protocol used gallium aluminum arsenide (GaAlAs) laser (wavelength 780 nm and power 70mW) during 60 seconds per 0.04 cm² of illuminated area for BP treatment (patient 1), and lasers emitting at 660 and 808 nm (power 600 mW) during 3 minutes per 2-3 cm² of illuminated area used synergistically with vacuum therapy equipment for trauma-based FN-palsy treatment (patient 2). Patient 1 received 2 sessions per week over 2 months and patient 2 over 3 months. LTTT treatments resulted in complete recovery of patients 1 and 2. No medication was administered during vacuum therapy and laser treatment. Normal facial expression was achieved including facial symmetry at rest and enhanced facial movement. Our results indicated that LLLT can enable nerve regeneration, as facial muscles recovered their normal functions. Based on these results, we believe laser therapy may be a viable approach to nerve regeneration and may have clinical relevance to be confirmed upon increasing patient numbers in future studies. Also, the combination between LLLT and vacuum therapy may arise as an alternative treatment to accelerate the recovery of the facial expression of FN-palsies and BP patients.